Vibrational enhancement of the effective donor-acceptor coupling

This letter deals with a simple three-site model for charge transfer phenomena in a one-dimensional donor (D)-bridge (B)-acceptor (A) system coupled with vibrational dynamics of the B site. It is found that, in a certain range of parameters, the vibrational coupling leads to an enhancement of the effective donor-acceptor electronic coupling as a result of the formation of the polaron on the B site. This enhancement of the charge transfer efficiency is maximum at the resonance, where the effective energy of the fluctuating B site coincides with the donor (acceptor) energy.